<p>If you <em>can</em> perceive a difference in the images, select <strong>Different</strong>.  If you <em>cannot</em> perceive a difference in the images, or you are unsure if they are different, select <strong>Identical</strong>.</p>

<p>If you want to withdraw at any time, close this browser window (or tab).  Your results will <em>not</em> be submitted.</p>
